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(No Model.) 7

S. D. LAKE.

BURGLAB ALARM.

Patented Jan. 31,1882.

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V Uwtrnn STATES PATENT @FHCE.

STEPHEN D. LAKE, OF JERSEY CITY, NEYV JERSEY, ASSIGNOR OF ONE-HALF TO ASA W. DICKINSON, OF SAME PLACE.

BURGLARALARi\/i.

SPECIFICATION forming part of Letters Patent No. 253,070, dated January 31, 1882,

Application filed December 10, 1881. (No model.)

To all 'whom it may concern:

Be it known that I, STEPHEN D. LAKE, a citizen of the United States, residing at Jersey City, in the county of Hudson and State of New Jersey, have invented certain new and useful Improvements in Burglar-Alarms, of which the following is a specification.

My invention relates to certain improvements in the construction of apparatus employed in electric burglar-alarms, and in the arrangement of circuits therefor.

The object of the invention is to organizethe apparatus and its connections in such a manner that an alarm shall be given whenever the x5 conductor traversing the building to be protected is broken, short-circuited, or tampered with in any way, whereby its electrical resistance is'materially altered.

To this end my invention comprises a main 2o battery having two electro-magnets or relays included in multiple arc therewith, each provided with an armature and circuit-closer, so adjusted with reference to each other by retracting-springs that the magnetism induced in one of the magnets by the current traversing its coils shall be just sufficient to over come the retractile force exerted upon its armature, while the magnetism simultaneously induced in the other shall not-be sufficient to 0 counteract the retractile force of its armature.

My invention further consists in the combination, with the above-described apparatus, of a local battery, two branch circuits, each in eluding one of the circuit-closing levers, and a 3 5 signal or alarm apparatus so arranged as to be set in action whenever a circuit is closed through either of the armatures and its contact-stop by the interruption or change in the resistance of the house-circuit.

In the accompanying drawing,I have shown an arrangement of circuits embodying the features of my invention.

E represents a main battery, one pole of Which is connected with a main-line wire, 1, 5 which traverses the house or building to be protected, being connected with the doors, windows, safes, vaults, and other exposed points in a well-known manner, returningto the other pole of the battery through the wire 7.

R and R represent two relays, arranged in multiple arc in the main line between the points 1 and 6. Theelectro-magnet R is provided with an armature mounted upon an armaturelever, 1', playing between the two stops at a. Of these the front stop, a, is provided with a point of insulating material, against which the lever r rests when in its normal position. The electro-magnet It is similarly providedwith a lever, r, playing between the two stops 1) I), andthe stop I) is insulated from itslever in the same manner as the stop a. The resistance of the circuits 2 3 and 4 5, including their respective magnets t and R, is made approxi mately equal, in order that the currents traversing them from the battery E may likewise'65 be equal. Aswitch, K, isincluded in the line 6, for convenience. in testing the condition of the connections and ofthe adjustment, and for placing the battery E upon an open circuit whenever required.

Each of the armature-levers r r is provided with an adjustable retractile spring, t t, for regulating the amount of mechanical resistance to, be overcome by the attractive force of the eleetro-magnet. The circuit of the battery E is normally closed, and the tension of the spring t is so adjusted that the armature-lever r'shall be permitted to be drawn toward the magnet R and to rest against the stop a by the action of the current traversing the coils of this magnet. The tension of the'other spring,

t, is such that the normal current traversing the electro-magnet R shall be not quite sufficient to attract the armature 1*, which therefore remainsin its normal position against the rear stop, I). The armature-levers r and r are included in multiple arc in the circuit of a local battery, e, and an alarm-bell or other suitable signaling apparatus, S, is includedin the same circuit. 0

The circuit-connections extend from one pole of the batterythrough the signaling apparatus to the levers r and r, and from the other pole of the battery to the stops 0. and b.

Each of the branch circuits, which include the armature-levers r r is provided with a switch, as shown at 70 and 70, respectively, for disconnectingthe lines when desired. The battery c is normally upon an open circuit; but

this circuit will be closed through the lever r 10 and its contact-stop (0 whenever the main line becomes disconnected or its resistance 1s 1ncreased, and through the lever r and its contact-stop 1) whenever the main-line resistance is decreased and the armature-lever r consequently attracted toward the magnet R and against this stop.

In case an attempt is made to inserta shuntcircuit for cutting out the main line traversing the building to be protected, thus causing a change of resistance therein, or in case the wire is severed, causing an interruption of the circuit, one or the other of the relays will be actuated, thus causing the circuit of the battery e to be closed and an alarm to be given from the signaling apparatus S. By including the relays It and It in multiple arc the resistance offered to the battery E is reduced, and a battery of considerably less electro'motive force may be employed than would be required were the magnets connected in series.

The switch It is employed for disconnecting the line ll 12, in order that the signaling apparatus may be cut out of circuit during the day or at other times when the alarm is not required for protection. It is evident that when the line l1 12 is disconnected no alarm will be sounded by the breaking of the housecircuit and the consequent retraction of the armature r againstits contact-stop 01, since the circuit will still beincomplete. When it is desired to set the alarm the switch It is closed. In case the house -circuit should be through inadvertence or design left open or disconnectedas. tor instance, at switch K-the lever r being still in contact through the signaling apparatus, the alarm will be actuated. A switch, It, is similarly included in the circuit of the lever r, to provide against an alarm being given on account of a decrease of resistance in the main circuit, or an increase in the strength of the battery at times when its protection is not required.

Suitable circuit-breakers of well-known construction are applied to the windows or doors of the buildings, safes, 850., to be protected, and are included in themain or house line (i 7. Suitable artificial resistances may also be included in the main line, when required,t'or the purpose of adjusting the relays R and B. These artiticial resistances may be employed either to measure the additional resistance required in the main line to cause the armaturelever 1' to fall back from the stop a, or to add a suflicient resistance to balance the main line when for any reason it is desired to cut out a portion of the same or to otherwise reduce the resistance thereof.

I claim as my invention- 1. The combination, substantially as here inhefore set forth, of a main battery, a main circuit, two relays included in said main circuit, a local battery, a local circuit having two branches connected respectively to the front contact-stop of one of said relays and the rear contact-stop of the other, and a signaling or alarm apparatus.

2. The combination, substantially as hereinbefore set forth, of a main battery, a main circuit, two relays included in said main circuit, a local battery, a local circuit having two branches connected respectively to the front contact-stop of one of said relays and the rear contact-stop of the other, a signaling or alarm apparatus, and a switch adapted to open or close said branch circuits.

3. The combination, substantially as hereinbefore set forth, of a main line, a main battery, two relays having their respective electro-magnets included in multiple arc with said battery and their circuit-breaking armaturelevers respectively included in two branches of a local circuit, a local battery, means for adjusting the retractile force exerted upon said armature-levers, and contact-stops for closing the local circuitthrough a signaling apparatus by the movement of either of said armaturelevers.

In testimony whereof I have hereunto subscribed my name this 8th day of December, A. D. 1881.

STE PHEN D. LAKE.

Witnesses CHARLES A. TERRY, MILLER O. EARL. 

